Composite brake shoe



April 12, 1932. T. P. CHASE COMPOSITE BRAKE SHOE Filed Dec. 51, 1928 LOW RELATIVE COEFFICJ EXPAN-SlON EFFICIE NSION RELATIVE Y HIGH 00 OF EKFA at... Apr. 12. 1932 UNITED- STATES PATENT OFFICE TERROR I. CHASE, OI DETROIT, IIOHIGAN, ASSIGHOB' TO" GENEBAL IO'IOBB CORPORATION,OI DETROIT, IIGKIGAIL A CORPORATION 01' DELAWARE I ooxrosn'r: mu snoa Application ma mi... :1, was. man 10-39.00.-

This invention relates to brakes. It hasbeen designed as an improvement in internal shoe brakes for vehicles, but its usefulness in other relations will be readily appreciated. The object of the invention is to make a composite brake shoe, the shoe being made of two metals having unlike coefficient of expansion whereby distortion due to temperature changes is reduced to a minimum.

Another object is to effect considerable economy in the manufacture of rigid shoes for internal brakes.

Other objects and advantages will be understood from the following description.

In the. drawings accompanyin the description are shown several embo iments of the invention. Fig. 1 is a view in side elevation of a brake shoe in accordance with my invention, partly broken away and-in section. Fig. 2 is a section on line22 of Fig. 1. Fig. 3 is a section on line 3-3 of Fig. 1. Fi 4 is a transverse section through a modi ed form and Fig. 5 is a longitudinal section of a brake shoe in accordance with this second form of the invention. Fig. 6 is a transverse section of a third way in which the invention may be carried out. Fig. 7 is a longitudinal section of this third form.

Referring to the reference characters in the drawings, numeral 9 designates in general a brake shoe of the usual arc shape. This shoe is intended to be pivotally anchored within the conventional brake drum to the fixed plate or backing plate. Atv one end the shoe is shown with an opening 11, this opening being intended for the reception of a pin by which the brake anchor means is pivotally connected to the shoe. Although the anchor -means for the brake is no part of this invention, it may be mentioned that the pin carried by opening 11 pivotally supports links which at their other end are pivotally connected to the backing plate. The opposite end of the shoe is arranged to be pushed outpreferred means may be arranged for this purpose. In order that the drawings may be complete, there is shown an end part 13 having an opening 15. This opening 15 is to receive a pin to provide the pivotal connecapplying means. Inasmuch as this brake ap- -ing carrying members 19, 21,23. While the wardly into engagement with the drum. Any

tion between the brake shoe 9 and a swinging member which is to'transmit the force delivered bythe rotating cam or other-brake plying means 18 no part of the invention, no further lllustratlon or description is believed to be necessary in this connection.

The brake shoe is formed of a beam designated by numeral 17 and'a plurality of linnumber of lining carrying portions isshown as three. it will be. understood that this num' ber may be varied as desired. It is intended that the lining carrying parts 19, 21 and 23 shall-be of steel and that the beam portion 17 shall be of aluminum. Other metals may beemployed as substitutes, it being intended that the metal constituting the beam shall have a relatively higher cocfiicient of expansion than the metal constituting the lining carrying parts' 1 Preferably the shoe will be formed by casting the aluminum beam in a suitable mold, the previously formed lining carrying parts being placed in the mold. Y j

The means of attachment between the lining carrying parts and the beam may take several forms, the drawings showing three of the forms which may be used.'- 'In Fig. 1 the .lining carrying portion is substantially of T-shape in section, this portion including a flange 25 and a web 27. The three lining car-. rying members 19, 21, and 23 are placed in the mold and thereafter the molten aluminum is poured in and surrounds the web 27 It will be noticed that there is a'little space between theadjacent ends of'the lining carrying portions. In order to secure a firm attachment between the lining carrying portions and the beam the former may be provided with suitable openings in the web portion thereof as at 31 so that when-the metal is poured in the mold it fills these openings and securely locks the lining carrying membersto the beam portion. .It should also be noted that these; openings are preferably located at about the middle of the length of the flanges.

.Another means of securing the l-iningcarrying portions to the beam is illustrated in 1 carrying parts of which one only, 21', is illustrated, is to be secured to the aluminum beam member 17 In this form of the invention the web shown at 27, Figure 1, is omitted. In place of the web portion a part of the flange is depressed as at 33. ThlS depressed portion is located at about the middle of the length of the lining carr ing portion 21'. By comparing Fig. 4 an Fig. 5 it will be seen that the depressed portion is com paratively narrow but relatively long and that the depth of the depression increases towards its ends, and that'the depression at its ends is cut away with the result that when the aluminum fills the mold it securely locks the middle portion of the lining carrying part to the beam.

Figs. 6 and 7 show still a third form which the invention may take. In this form a portion of the lining carrying member near the middle thereof 1s cut out to form a narrow but relatively longer opening. The edges of this opening are turned down as illustrated in Fig. 7 so that the aluminum of the beam surrounds the edges and firmly locks the lining carrying part to the beam.

It will be understood that these are merely illustrative of numerous ways which might be ado ted to secure the lining carrying parts to t e beam. 7

It should be explained that the part of the brake shoe which is nearer the drum becomes more highly heated than the beam portion, the latter -being further removed from the source of heat. The more highly heated part is therefore formed from a metal having a lower coeflicient of expansion and the less tion tends to cause the brake to either lack eiliciency or to be grabby. v

It is well known that aluminum is far more expensive than steel and by using steel for the outer portion and aluminum for the beam portion it will be seen that a very considerable cost reduction may be secured. The division of the steel flange in the three sections is to provide for the difierence in expansion of the aluminum and the steel, shrinkage and the expansion of the aluminum being provided'for by the space between the adjacent ends of the steel sections. The attachment of the steel sections to the aluminum beam is preferably near the middle point of the former to avoid relative movement between the two metals which have difierent coeflicients strenu.

LUBSJOQ I claim:

1 brake shoe having a beam portion and a lining carrying portion, the beam portion formed from a metal having a relatively greater coeflicient of expansion, the lining carryin portion being in the form of a plurahty o longitudinal y arranged sections.

2. A brake shoe having a beam'portion formed from a metal of a relatively greater coefficient of expansion and a lining carrying portion having a lower 'coeflicient of expanson, the lining carrying portion being in the form of aplurality of ongitudinally spaced sections, each section being attached to the beam at a point intermediate its length.

3. A brake shoe having a beam of aluminum and a flange of steel, the steel flange comprising a plurality of longitudinally arranged sections, each section being independently secured to the beam.

4. The invention set forth in claim 3, said securlng means being located adjacent the middle of the length of the section.

5. A brake shoe having a steel flange and an aluminum beam, the flange being in sections, each section having a longitudinal web constructed to be secured to said beam at an intermediate point of its length.

6. The invention set forth in claim 5, said attachment being arranged by the provision of an opening in the .web to receive the metals of beam.

In testimony whereof I aflix my si THERON P.

ature. SE. 

